Micromagnetic calculation of the transverse susceptibility of patterned media

In this paper, we present a generalized model of the transverse susceptibility (TS) for realistic fine particle systems that may have any type of anisotropy (uniaxial,cubic,or unidirectional), distribution of easy axes orientation, particles positions and volumes and different strength of magnetostatic interactions between particles. The field dependence of TS is obtained using a micromagnetic algorithm based on the Landau-Lifshitz-Gilbert equation. For the uniaxial particles, where the critical curve approach can also be used, we have compared the results of the micromagnetic algorithm and those obtained by integration of Aharoni's formula over the orientation distribution. Tests were also made on the calculation of the TS for single particles with various orientation of the easy axis with respect to the AC/DC applied fields.